Crowning attachment for roll grinding machines



Aug. 14, 1934. H. w. DUNBAR ET AL CROWNTNG ATTACHMENT FOR ROLL GRINDING MACHINES Filed Dec. 4, 1953 HOWARD W. UUNBAR CARL G.F LYGARE W TNESS awa-m 6W wwa m Patented Aug. 14, 1934 UNITED STATES CROWNING ATTACHMENT FOR ROLE GRINDING MACHINES Howard W. Dunbar and Carl G. Flygare,

Worcester, Mass, assignors to Norton Company, Worcester, Massachusetts Mass,

a corporation oi.

Application December 4, 1933, Serial No. 700,794

Claims.

This invention relates to grinding machines for grinding rolls, and more particularly to a forming or crowning attachment for producing a predetermined crown on the surface of the roll.

Heretofore, numerous forming or crowning attachments have been developed and utilized in the grinding of rolls to produce the desired c'urva- 1 ture on the surface of the roll. Various types of mechanisms have been utilized including flexible forming bars, rigid forming bars, and also adjustable supports for the roll being ground which enabled the axis of the roll to be skewed relative to the axis of the grinding wheel.

In grinding rolls for certain of the rolling mill operations,- it is necessary to provide the periphery of the roll with a surface of the proper crown, as well as a mirror surface, since any irregularities or imperfections in the surface of the roll are reproduced in the product rolled by the mill. It

is, therefore, essential that the rollbe very accurately ground with a surface of the desired quality, as well as to be ground with a crown so that when two opposed rolls are mounted in the rolling mill, they will produce a product rolled between them which meets the required specifications.

It has been found, through years of experience and numerous tests which have been conducted with the various roll forming attachments which are now utilized, that there is a bowing or flexing of the swivel table supporting the roll during grinding, due to the pressures exerted by the forming apparatus and the pressure of the grinding wheel.

It is a primary object of this invention to provide a suitable fluidpressure operated mechanism controlled by a forming bar to cause a relative transverse movement between the wheel and work as the wheel and work are traversed longitudinally relative to each other to produce a desired and predetermined crown or form on the roll being ground.

It is one object of this invention to provide a suitable forming attachment which provides means for initially bowing or flexing the swivel table by an amount equal to the normal flexing, as experienced in previous attachments, so that in production, flexing of the table due to thrusts and pressures in the forming operation is eliminated.

It is a further object of this invention to provide a fluid pressure actuated roll forming or crowning apparatus which is arranged so that a relatively coarse movement by a forming bar is reduced by the fluid pressure mechanism to cause a minute relative transverse movement between the grinding wheel and the work. Other objects will be apparent from the foregoing disclosure.

One embodiment of this invention has been illustrated in the drawing, in which like reference numerals indicate like parts.

Fig. 1 is a front elevation of a grinding machine embodying the hydraulic roll forming attachment;

Fig. 2 is a diagrammatic view showing the arrangement of the hydraulic crowning or forming attachment;

Fig. 3 is a fragmentary vertical section, on an enlarged scale, taken substantially on the line 3-3 of Fig. 1; and

Fig. 4 is a fragmentary cross-sectional view, taken approximately on the line 4-4 of Fig. 1, showing the hand table traverse mechanism and the pivot for the swivel table.

This invention comprises broadly a roll grinding machine in which the roll to be ground is rotatably supported on a swivel table. The swivel table is mounted on a longitudinally movable work table which is arranged to be reciprocated longitudinally to carry the roll to be ground past the periphery of the grinding wheel. A fluid pressure mechanism is interposed at opposite ends of the table between the longitudinally movable table and the swivel table and is arranged to swing the swivel table as it moves longitudinally to produce a predetermined crown on the periphery of the roll being ground.

A forming bar is provided to actuate a piston as the table reciprocates to cause a movement of fluid within the system to produce the desired swiveling of the work supporting table as the table is reciprocated to carry the roll past the grinding wheel. In the preferred form, the 4 forming bar is a straight bar which is adjustably mounted so that the crown produced on the roll may be varied as desired.

As illustrated in the drawing, a roll grinding machine has been shown having a base 10 which is provided with the usual V-way and flat way (not shown) to support a longitudinally movable work table 11. A swiveltable 12 is mounted on the upper surface of the table 11 and is connected thereto by a pivot pin 13. A suitable headstock 14 is mounted on one end of the swivel table 12 and a footstock 15 adjustably mounted on the other end of the swivel table 12. The head and foot stocks are arranged to rotatably support a roll 16 to be ground in operative relation with a rotatable grinding wheel 17. The grinding wheel is supported on a wheel slide 18 which is arranged for a transverse feeding movement relative to the base 10 in a manner such as is common practice in the cylindrical grinding field. For example, see the prior U. S. patent to Norton No. 762,838 dated June 14, 1904. For further reference to the details of arrangement of the wheel slide support, reference may be had to the prior patent to Norton.

The grinding wheel may be fed toward and from the roll 16 by means of a wheel feeding mechanism 25 which has been illustrated only in elevation in the drawing. The feeding mechanism is not considered a. part of the present invention, and consequently has not been illustrated; in detail. This -mechanism corresponds with and is substantially identical to the mechanism shown in the prior U. S. patent to Norton above referred to. For further details as to the feeding mechanism, reference may be had to the prior patent. The feeding mechanism is arranged so that it may be manually rotated when desired by the operator or may be actuated by adjustable dogs 26 and.27 on the table 11 at the ends of the table stroke, as is common practice in the cylindrical grinding field. For details of the actuating mechanism for the feed wheel 25, reference may be had to the prior patent above referred to.

Table traverse The work supporting table 11 may be traversed by a suitable power actuated mechanism, as is shown in the prior U. S. patent to Norton No. 762,838. The prior mechanism for reciprocating the table 11 has not been shown in detail, only the parts shown in the front elevation having been illustrated. This mechanism is not considered a part of the present invention and for details of the construction and its operation, reference may be had to the above mentioned patent. The table 11 may, if desired, be traversed manually by means of a hand wheel 30 which is mounted on the outer end of a shaft 31 carrying a gear 32 at its inner end. The gear 32 meshes with a larger gear 33 on a shaft 34 which is rotatably supported in suitable bearings in the base 10. Theshaft 34 carries a pinion 35 meshing with a rack 36 on the under side of the table 11. It will be readily apparent from the illustration in the drawing and the foregoing description that manual rotation of the hand wheel 30 serves through the gear mechanism to traverce the table 11 in either direction to cause a relative motion between the roll 16 and the grinding wheel 17.

Forming attachment To attain the main object of this invention, a hydraulic. mechanism is provided for causing a 1 relative swiveling motion between the swivel table 12 and the longitudinally movable table 11.

The fluid pressure system, as illustrated, comprises cylinders 35 and 36 which are rigidly mounted on the opposite ends of the longitudinally movable work table 11. The cylinders 35 and 36 are provided with pistons 37 and 38 respectively, which are arranged to move longitudinally of the cylinders. The pistons 3'7 and 38- are provided with piston rods 39 and 40 respectively, which are connected by links 41 and 42 respectively with projections 43 and 4A respectively which extend from and are rigidly secured to opposite ends of the swivel table 12. The link 41 is pivotally connected to the piston rod 39 by a pin 50, and is connected by a pin 51 to the bracket 43. Similarly, the pins 52 and 53 pivotally connect the link 42 to the piston rod and to the bracket 44. A pipe 56 operatively connects the cylinder chamber 57 in cylinder 35 with cylinder chamber 58 in cylinder 36, so that fluid may readily pass from one chamber to the other.

To cause the necessary motion of the fluid pressure piston so as to swivel the table 12 to produce the desired crown, a suitable fluid pressure piston 60 and cylinder 61 are provided to cause a definite movement of the fluid within the system. To eliminate the necessity for a fine adjustment of the forming bar, it is desirableto provide a system whereby a given movement transmitted by the forming bar is reduced to cause a relatively smaller movement of the swivel table. In the preferred embodiment as illustrated, the area of piston 60 is much less than the area of the piston 37; so that the displacement of fluid caused by a given movement of the piston 60 causes a relatively smaller movement of the piston 37. By varying the ratio of the areas of pistons 60 and 37, any desired amplification or reduction of motion may be obtained.

In order that the swivel table may be moved to produce a predetermined curvature on the periphery of the roll, a forming bar is provided which is operatively connected to move the piston 60 and cause a movement of the fluid within the fluid pressure system to cause a swiveling movement of the table 12 relative to the table 11 as it reciprocates. In the preferred form, as illustrated in the drawing, a straight bar 63 is pivotally mounted on a stud 64 and is arranged to be clamped to the base by means of the screws 65 and 66, which permits the bar to be readily adjusted so that it is either parallel to or at an angle to the path of movement of the table 11. A slide 66 is slidably supported on the bar 63 and is pivotally connected to a piston rod 62 which in turn is rigidly fixed to the piston 60. A rod 69 is fixed to a bracket 70 projecting from and rigid with cylinder 35 and is slidably mounted in a sleeve 71 which is pivotally mounted by a stud '72 on the slide 66.

Assuming the bar 63- to be in the position illustrated in Figs. 1 and 2, when the table 11 is reciprocated, as, for example, toward the left, the movement of the table 11 causes a corresponding movement of the slide 66 along the bar 63. the piston rod 62, causing a movement of the piston 60 to force fluid under pressure from cylinder chamber into cylinder chamber 81 to cause the swivel table'to move in a counterclockwise direction, as viewed in Fig. 2. As fluid is forced into cylinder chamber 81, moving piston 37 downwardly, as viewed in Fig. 2, this in turn serves to transmit a similar motion to the piston 38 through the column of fluid in cylinder chambers 57 and 58 and pipe 56. Similarly, p eversal of the table as the table 11 starts This movement of slide 66 serves to raise.

moving toward the right after it has reached the end of, its travel, the slide 66 moving down the bar 63 causes a downward movement of the piston 60 in the cylinder and serves to force fluid from cylinder chamber 85 through conduit 86 into cylinder chamber 87 to cause the swivel table 12 to move in a clockwise direction as the table moves. As fluid is forced into cylinder chamber 87, the piston 38 moves downwardly,.

as viewed in Fig. 2, forcing the column of fluid in cylinder chamber 58, pipe 56, chamber 57, to cause a corresponding movement of the piston 37 in the opposite direction.

It will be readily apparent from the foregoing disclosure that by adjusting the angular position of the bar 63 relative to the path of movement of the table 11, the curvature or crown on the roll being ground may be varied to give a predetermined lengthwise curvature on the periphery of the roll. Or, if desired, to grind a true cylinder, the bar 63 may be adjusted so that it is arranged parallel with the path of movement of the table 11. If the bar, is adjusted to this position and the table is then reciprocated, the movement of the slide 66 along the bar 63 does not transmit any motion to the piston 60, and consequently no swiveling of the table 12 is produced and a true cylindrical surface may be obtained on the periphery of the cylinder or roll being ground.

It has been found, through years of experience and experimentation in the roll grinding field, that difliculty is encountered in forming rolls due to the fact that the parts of the machine have a certain amount of spring or give when put under strain. For example, the swivel table, such as table 12, when subjected to the pressures of a roll forming attachment for swiveling the table as it travels, as well as the pressure of the grinding wheel exerted upon the work, causes the table to spring or how during use. It is desirable to compensate for this spring or bow in the swivel table and to either provide adjustment in the forming apparatus or otherwise to eliminate this factor. One feature of the present apparatus comprises the provision of adjustable valves 90 and 91, which are connected by pipes 92 and 93 respectively with cylinder chambers 81 and 87 of cylinders 35 and 36 respectively. The valves 90 and 91 are provided with adjustable pistons 94 and 95, which are arranged for adjustment by means of screws 96 and 9'7 respectively. Assuming the system has been filled with oil or other fluid, it is possible by manipulation of the pistons 94 and 95 to increase or decrease the pressure in the chambers 81 and 87. By adjusting the pressure on each side of the piston 60, the swivel table 12 may bebowed or sprung slightly to take up any normal spring in the table, as well as to eliminate lost motion in the link connection between the piston rods 39 "and 40 and the swivel table 12 respectively.

p A pressure adjusting valve 100 having a piston 101 and chamber 102 is connected by a pipe 103 with the cylinder chamber 58. The piston is yieldably held against the fluid by means of a spring 105 to put a definite pressure on the oil Within the system between the cylinder cham ber 57, pipe 56 and the chamber 58. This en ables the fluid within this part of the system to be adjusted to produce a definite back pressure on the pistons 37 and 38, so that when one of the pistons is moved, a corresponding movement will be transmitted to the other piston so that each end of the swivel table 12 will be moved through a predetermined extent. The provision of the pressure adjusting valve 100 also serves to compensate for any adjustment of the adjusting valves 90 and 91. The yieldable spring 105 serves to maintain a predetermined pressure on the fluid and is sufliciently resilient to allow expansion of the fluid within this system when the valves 90 and 91 are adjusted. A piston rod 106 is fixed to piston 101 and extends through the end of the cylinder. A pair of lock nuts 107 on a threaded portion 108 of the piston rod serve to permit the retraction of piston 101 against the tension of spring 105 when desired.

The operation of the mechanism will be readily apparent from the foregoing disclosure. Assuming the adjusting valves 90 and 91 to have been previously adjusted and the fluid system filled with oil and the valve 100 adjusted to give a predetermined back pressure on the other side of the system, and also assuming the bar 63 to have been adjusted to the predetermined extent, the operator starts the traversing movement of the table 11. -This movement of the table 11 causes a corresponding movement of the slide 66 on bar 63 and serves to transmit motion to the piston 60, causing a movement of the fluid within the pressure system to cause a swinging movement of the swivel table 11 relative to the table 12 to produce the predetermined crown on the periphery of the roll.

If the .bar 63 is adjusted into the full line position, as indicated in Figs. 1 and 2, a convexity or crown is produced on the periphery of the roll being ground. If it is desired to produce a concaved surface on the roll, the bar 63 is adjusted into position 63 (Fig. 2).

A scale 110 is mounted on the front of thebase of the'machine to enable the operator to readily adjust the bar to a predetermined position. By utilizing a previously calculated table, the operator may readily adjust the bar to produce the desired crown. That is, if the operator wants to produce a ten one-thousandth of an inch crown at the center of the roll, that is, the center portion being ten one-thousandths of an inch greater than the end portion, the table will give the desired scale setting for the bar 63. The operator, by adjusting the bar to the required setting on the scale, may produce a crown of the desired curvature. If the operator finds that one end of the roll or the other varies slightly in diameter and it is necessary to compensate to equalize the end diameters of the roll, this may be accomplished'by adjusting the valve 90 or the valve 91. This will be readily apparent from the foregoing disclosure. By increasing the pressure in chamber87, the'piston 38 is moved to cause the table 12 to swing in a clockwise direction, thus increasing the diameter at the right-hand end of the roll; or, if the right-hand end of the roll 16 were larger in diameter than the left-hand end, the operator would retract the piston 95 in valve 98 slightly, relieving the pressure in the chamber 87, and'cause an-adjust-, ment of the table 12 in a counterclockwise direction so as to bring the right-hand end of the roll nearer to the axis of the grinding wheel and thereby cause the same to be ground to a smaller The grinding machine illustrated and described is of the type having a transversely movable grinding wheel and a longitudinally reciprocable work table which supports a relatively movable swivel table arranged for producing the desired crown or form on the roll being ground. This invention, however, is equally applicable to a grinding machine in which the grinding wheel slide is pivotally mounted so that it may be swivelled, such as by a forming bar carried by the reciprocable Work table, or the grinding wheel slide may be pivotally carried by a reciprocable carriage and a forming bar on the base arranged to cause the desired swivelling of the wheel slide to produce a predetermined crown on the periphery of the roll being ground. This invention is also applicable to a grinding machine of the type in which the work table is reciprocable longitudinally and the transversely movable grinding wheel slide is pivotally mounted for a transverse rocking movement which may be controlled by a forming bar on the base. In each of the arrangements set forth above, the fluid pressure apparatus is interposed between the forming bar and the swivelled or pivoted member to cause a predetermined form to be ground on the periphery of the roll. In

any application of this invention, an amplification is provided in the fluid pressure system whereby the motion initiated by the forming bar is reduced to cause a relatively small motion to the swivelled or pivoted member in producing the predetermined crown or form on the periphery of the roll. By utilizing such a reduction in the fluid pressure actuating mechanism, it substantially eliminates the necessity for a fine adjustment of the forming bar.

Having thus described our invention, what we claim as new and desire to secure by Letters Patcuts:

1. A grinding machine comprising a rotatable grinding wheel and a rotatable work support which are movable transversely and longitudinally relative to each other, means to move one of said members relatively towards and from the other to produce the desired feeding movement to grind the work to a predetermined size, a fluid pressure system including a piston and cylinder operatively connected to cause a relative transverse movement between said wheel and support as they are reciprocated longitudinally relative to each other, a forming bar, and means operated by said bar for actuating said fluid pressure system to produce a predetermined crown or form on the work being ground.

' 2. A grinding machine comprising a rotatable grinding wheel and a rotatable work support which are movable transversely and longitudinally relative to each other, means to move one or said members relatively towards and from the other to, produce the desired feeding movement to grind the work to a predetermined size, a fluid pressure system including a piston and cylinder operatively connected to cause a relative which are movable transversely and longitudinally relative to each other, means to move one of said members relatively towards and from the other to produce the desired feeding movement to grind the work to a predetermined size, a fluid pressure system including a piston and cylinder at each end of one of said members which are operatively connected to cause a relative swivelling movement therebetween as they are reciprocated longitudinally relative to each other, a forming bar, and means operated by said bar for actuating said fluid pressure system to produce a predetermined crown or form on the work being ground.

4. A grinding machine comprising a rotatable grinding wheel and a rotatable work support which are movable transversely andlongitudinal- 1y relative to each other, means to move one of said members relatively towards and from the other to produce the desired feeding movement to grind the work to a predetermined size, a fluid pressure system including a piston and cylinder' at each end of one of said members which are operatively connected to cause a relative swivelling movement therebetween as they are reciprocated longitudinally relative to each other, a forming bar, and means operated by said bar for simultaneously actuating fluid in each of said cylinders of said system to produce a predetermined crown or form on the work being ground.

5. A grinding machine comprising a rotatable grinding wheel and a rotatable work support which are movable transversely and longitudinally relative to each other, means to move one of said members relatively toward and from the other to produce the desired feeding movement to grind the work to a predetermined size, a pivotal support for one of said members, a fluid pressure system including a piston and cylinder operatively connected to cause a transverse movement of said pivoted member as said members are reciprocated longitudinally relative to each other, a forming bar, and means operated by said bar for actuating said fluid pressure system to produce a predetermined crown or form on the work being ground.

6. A grinding machine comprising a rotatable grinding wheel and a rotatable work support which are movable transversely and longitudinallyrelative to each other, means to move one of said members relatively toward and from the other to produce the desired feeding movement to grind the work to a predetermined size, a pivotal support for one of said members, a fluid pressure system including a piston and cylinder at each end of one of said members which are operatively connected to cause a relative swivelling movement therebetween as they are reciprocated longitudinally relative to each other, a forming bar, and means operated by said bar for actuating said fluid pressure system to produce a predetermined crown or form on the work being ground.

7. A grinding machine having a transversely movable wheel slide, a longitudinally movable work table, a pivotally mounted support on said table for rotatably supporting a roll to be ground, an angularly' adjustable forming bar mounted on the base, a slide guided by said bar and moved longitudinally on said bar by said table, a fluid pressure system including a piston and cylinder operatively connected between the sliding table and the swivel table, and means actuated by said slide as it moves along the bar to actuate the fluid in said system so as to cause a movement of the swivel table relative to the table as it moves longitudinally to produce the desired crown on the roll being ground.

8. A forming attachment for a roll grinding machine having a transversely movable wheel slide, a longitudinally movable table, a swivel table supported on said table having means to rotatably support a work piece, a forming bar adjustably mounted on the base, a fluid pressure system including a piston and cylinder operatively connected between the longitudinal table and the swivel table, a slide engaging and movably supported on said bar which is moved longitudinally by said table, and a fluid pressure piston and cylinder actuated by said slide as it moves along said bar to actuate the fluid in said first cylinder to cause a swivelling movement of the work'support as the table moves longitudinally to produce the desired crown on the roll being ground.

9. In a roll grinding machine having a transversely movable wheel -slide,. a longitudinally movable table, a work supporting member pivotally mounted on said table and arranged to rotatably support a work piece in operative relation with the grinding wheels, and a forming apparatus including a bar adjustably positioned on the base, a fluid pressure system including a piston and cylinder operatively connected between the ends of the longitudinally movable table and the swivel table, a slide carried by said bar, and a piston actuated by said slide as the slide moves longitudinally with the work table which is arranged to simultaneously force fluid into opposite ends of said cylinders to cause a swiveling movement of the work support as the table moves longitudinally to produce the desired form on the periphery of the roll.

10. A forming attachment for roll grinding machines according to claim 9 in which each of the piston and cylinder mechanisms is provided with an adjustable valve arranged to apply a pressure to the fluid on each side of the piston so as to place an initial strain upon the swivel table sufilcient to remove the spring from the table so that the work support swivels on the table as it moves longitudinally to accurately produce the desired crown on the roll being ground.

HOWARD W. DUNBAR. CARL G. FLYGARE. 

